Edit: Thanks for your kind comments on disabling contributions. I'm aware of the possibility, this is just a meme.
Contributions in open source projects are great, needed and make the world a better place after all. Therefore they should be declined politely, optionally by giving a reason.
I hereby inform you that I will no longer accept contributions to this post /s.
Issues, yes. It's not possible to disable PRs though.
Ooops, I misremembered :(
It's okay. I like your version of reality better.. It's really ridiculous that we can't disable PRs there.